SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74b4d1eed895b96e79c831d1f4b41b7b277d48e45fe5ba7efef4bde7ad96f057' 
  AND token = '1UFX7oSkyoEJf+4+HFmUwOcIGSienQyed9XfXqweC+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}